The present invention relates to a device for centering rods fed to a lathe.
In automatic rod feeders centering units are arranged along the rod path towards the lathe chuck to hold the rod well centered with respect to the chuck and support it during rapid rotation. Clearly, in automatic feeders it is of primary importance to reduce to a minimum the vibrations which could be produced because of misalignment of the rod during rotation, vibrations which would increase machine noise and would reduce machining accuracy.
Centering devices arranged immediately upstream of the chuck confine the rod laterally to bring it back to satisfactory linearity near the chuck. The centering action must be effective but at the same time the rod must not be excessively constrained in order not to prevent discharge of vibrations within the magazine guides. Lateral confinement must therefore have a predetermined play which must be adjustable depending on the changing rod diameter. The centering unit must also have sufficiently expandable passage to permit transit of the rear grasping collet of the magazine which has greater diameter than the rod.
It is clear that providing a satisfactory centering unit is difficult and especially in the case of multichuck lathe magazines the solutions thus far found are very costly and complicated as they call for numerous moving parts.
The general purpose of the present invention is to obviate the above mentioned shortcomings by supplying a centering device which would permit perfect centering of rods fed to a lathe without obstructing magazine operation and which would have a simple robust structure even in case of multiple embodiment for use in a multichuck lathe magazine.